1. Field of the Invention
The present invention relates generally to circuit interrupters and more particularly to a bushing assembly that provides a circuit-interrupting function for electrical equipment such as a power transformer or the like, the bushing assembly being mounted so as to extend through the housing of the electrical equipment and incorporating a circuit interrupter and providing electrical connection between the exterior power source connections and the internal input connection to the transformer or the like.
2. Description of Related Art
Power transformers and other electrical equipment in the electrical transmission and distribution field are connected to a power source through various combinations of switching and protection devices so as to provide the required protection to the power transformers and electrical equipment as well as desirable versatility and flexibility in supplying the various load circuits in the electrical power system. The switching and/or protective devices include fuses, circuit breakers, and load-break disconnect switches. Typically, these switching and/or protective devices are independent of the power transformer or other electrical equipment in that these devices are separately supported with respect to the ground or a floor and include separate electrical interconnections between these devices and the supplied power transformer or other electrical equipment. For example, see U.S. Pat. Nos. 3,588,406 and 2,979,591. U.S. Pat. No. 4,663,504 illustrates a load-break switch, useful in at least the lower half of the medium voltage range (1-69 kV), that includes a grounded housing with bushings mounted at either end. In one arrangement, the switch is externally connected to a power transformer or other electrical equipment via an elbow connector. Another type of load-break switch, shown in U.S. Pat. No. 4,082,932, includes a metallic tank that is mounted on a wall within electrical equipment, the electrical connections to the load-break switch extending on either side of the wall. U.S. Pat. Nos. 2,662,947 and 2,866,032 illustrate fuse cutouts with bridging or recloser switches that are mounted within a bushing that provides electrical interconnection to the transformer on which the bushing is mounted, with the fusible elements of the fuse cutouts and the switching contacts being immersed within the dielectric fluid of the transformer.
While these various arrangements are generally useful, it would be desirable to provide circuit-interrupting functions for a power transformer or the like via an arrangement that is compact and of minimal additional size and cost to the transformer or other electrical equipment to be protected, while not contaminating the interior of the power transformer or the like with the are products of interruption.